A fuel cell, such as a polymer electrolyte fuel cell converts the chemical energy of a substance directly into electrical energy by the electrochemical reaction of reaction gases (fuel gas and oxidizing gas) supplied to a pair of electrodes (anode and cathode) arranged across an electrolyte membrane.
In the fuel cell, it is known in the art that providing a gas flow path layer made of expanded metal (metal lath) between a power generation layer including an electrolyte membrane and a pair of electrodes and a separator improves the diffusivity of the reaction gas and increases the power generation efficiency of the fuel cell.